The present disclosure relates generally to a pneumatic system and associated valves used to control a flow of gas from a higher-pressure source supplied to a lower-pressure container.
One type of pressurized container of gas is a dunnage bag. Dunnage bags are used to secure cargo of tractor trailers, railroad cars, and other vehicles. The dunnage bags are inflated on the sides of the cargo, such as between the cargo and walls of the respective vehicle. Once inflated, the dunnage bags provide a secure fit for the cargo in the vehicle, preventing unintended and undesired movement of the cargo during transportation thereof.
Typically the dunnage bags are formed from paper and interiorly lined with plastic. Other dunnage bags may be formed entirely from plastic. Paper and plastic materials allow for inexpensive manufacturing and replacement of dunnage bags, however the materials are not generally designed to withstand pressures above around 10 to 15 pounds per square inch (psi). During use, the dunnage bags are ideally inflated to pressures of about 2 psi, substantially below the pressures at which the dunnage bags would fail.
A typical tractor trailer may use twenty or more dunnage bags at a time, such as using ten or more on each side of the interior of the trailer. A trucker or loader using the dunnage bags must manually position and inflate each dunnage bag to secure the cargo. Once positioned between the cargo and a wall of the vehicle, the dunnage bags are typically inflated by a pressure-regulated pneumatic supply. The supply pressure is regulated to a safe pressure for the dunnage bags, typically around 2 psi. Inflating the dunnage bags by a regulated source providing air at 2 psi typically corresponds to a relatively low air flow rate for inflation of the bags. Accordingly, the task of securing the cargo by positioning and inflating each dunnage bag can be quite time consuming.